Schoenus arenicolus T.L.Elliott & Muasya

Elliott, T. L. & Muasya, A. M., 2018, A taxonomic revision of Schoenus compar - Schoenus pictus and allies (Cyperaceae, tribe Schoeneae) with three new species described from South Africa *, South African Journal of Botany 114, pp. 303-315 : 308

2. Schoenus arenicolus T.L.Elliott & Muasya in S. African J. Bot. 112: 359 (2017),

non Schoenus brachyphyllus J.M.Black (1929) ; Tetraria brachyphylla Levyns, J. S. African Bot. 13: 90 (1947). Type: South Africa, Western Cape Province, 3418 (Simonstown); slopes of Kapitein's Peak, Hout Bay, (–AB), 20 Oct 1946, Levyns 8093 (BOL, holo! [BOL139415]; BOL! [BOL139413, BOL139414], K!, PRE!, SAM - image!, iso.)

Tetraria sylvatica var. pseudocuspidata Kük, Repert. Spec. Nov. Regni. Veg. 29: 188 (1931). Type: South Africa, Western Cape Province, 3419 (Caledon); ‘in collibus pone Rhenosterkopp’, (–DD), 28 Apr 1897, Schlechter 10,570 (PRE, lecto.!, here designated; BM!, GRA!, K!, S - image!, P[P00461872, P00461873, P00461874] - image!, WAG[WAG0389326, WAG0108275] - image!, L - image!, isolecto.)

Caespitose, phyllopodic perennial graminoid. Often partly or almost entirely viscous, especially on sheaths and inflorescences. Culms terete, (206–)335–575(− 688) × 0.6–1.0(− 1.5) mm. Leaves basal, 2–5, short, (10.0–)25.0–68.0(− 134.0) × 0.2–0.7(− 1.2) mm, flat, usually not proximally channelled, straight or less often not, margin usually serrate above sheath. Sheaths often reddish-brown colour, smooth, often viscous, tightly clasping culm, longitudinally striate. Ligule membranaceous, 2-lobed, (1.9–)3.5–6.0(− 8.3) mm. In fl orescence a narrow panicle, 9.5–25.5(− 46.0) × (2.5–)4.0–6.0(− 10.0) mm, sometimes viscous, proximal rachis length 5.5–11.5(− 16.0) mm. Proximal primary in fl orescence bracts firm, non-sheathing, 25–77(− 173) mm long, often exceeding length of inflorescence several times, can have small membranaceous extensions at base. Spikes few, 1–5, 7.0–12.0(− 22.0) mm long. Spikelets 5.7–8.2(− 10.0) × 1.0–2.4(− 3.8) mm, usually paired with one sessile and the other with a short pedicel, oblong to lanceolate, 1–3 spikelets/spike. Rachilla 0.2–2.0(− 4.9) mm long. Glumes (1–)3–5 per spikelet, proximal glume (1.6–)2.6–3.2(− 3.6) mm long, subproximal glume 2.4–3.6(− 4.6) mm long, thick, firm, often shiny, distichous, more or less 2- ranked, reddish-brown, sometimes with a narrow scarious margin, upper glumes longer in length, prophylls with notable, raised vein extending to mucro. Mucros well-developed, proximal mucro length (0.1–)0.8–1.4(− 3.0) mm, subproximal mucro length (0.1–)0.5–1.0(− 2.2) mm. Stamens 3(− 9) per floret, anthers 3.3–4.7 mm long. Stigmas (2–)3-branched. Perianth bristles 0. Nutlet smooth below, broad elliptic, slightly trigonous, 3.1–4.9(− 5.8) × 1.5–2.4 mm. Nutlet beak conical, almost smooth, continuous with the lower part of nutlet, with faint longitudinal furrows, (0.5–)1.6–2.0(− 2.6) mm long. ( Figs. 1 and 2 ).

Flowering: September to December

Distribution and ecology: the distribution of S. arenicolus is mostly near the southwestern coast of South Africa, ranging from the Cape Peninsula in the west to the Knysna area in the east ( Fig. 4 ). This species generally grows on well-drained sandy sites among fynbos vegetation at low elevations (sea level to approximately 185 m).

Diagnosis: Schoenus arenicolus can be distinguished from most other species in this group by its reddish-brown leaf sheaths and relatively narrow inflorescences, which often have only three to six spikelets. It is a similar species to S. compar , from which it can be differentiated by its shorter leaves and reddish-brown leaf sheaths as opposed to the ivory sheaths of S. compar . Furthermore, S. arenicolus has much fewer spikes and spikelets, as well as nutlet beaks that are continuous with the nutlet body and smoother compared to those of S. compar .

Additional collections examined

South Africa. WESTERN CAPE: 3318 (Cape Town): Near the Stellenbosch Division, boundary on the Klipfontein Rd., (–DC), 19 Dec 1962, Esterhuysen 29,966 (BOL, K); Klipfontein Road near Duinendal, (–DC), 12 Sep 1943, Levyns 7588 (BOL); Stikland, Cape Flats, dunes near power station, (–DC), 30 Aug 1979, Boucher 4505 (NBG); Cape Flats Nature Reserve – Bellville, University of Cape Town, (–DC), 27 Oct 1978, Low 740 (NBG). 3418 (Simonstown): Sandy flats between Fish Hoek and Noord Hoek, (–AB), Sep 1921, Pillans 4866 (K); Headland at Witsand, (–AB), Jan 1923, Pillans 4777 (K); N of Wildevoëlvlei, (–AB), 24 Nov 1983, O'Callaghan 707 (NBG); Platboom road, Cape Point Reserve, (–AD), 26 Sep 1978, Esterhuysen 35,034a (BOL); The Meadows Cape Point, (–AD), 7 Dec 1965, Taylor 6620 (NU, PRE); dune beyond Gifkommetjie turn-off, Cape of Good Hope Nature Reserve, (–AD), 7 Sep 1972, Taylor 8180 (NBG); Phillipi - Mitchell's plain, (–BA), 23 Aug 1998, Low PM 25 (GRA); Swartklip Road, (–BA), 9 Aug 1991, Berry 18 (NBG); Betty's Bay, Hangklip Estates, (–BD), 7 Feb 1944, Levyns 7668 (BOL); Hangklip Subregion, Blesberg lower slopes along vehicle track, (–BD), 4 Mar 2001, Joubert 435 (NBG); Buffels River mouth, Pringle Bay, (–BD), 17 Nov 1971, Boucher 1743 (NBG). 3419 (Caledon): Wortelgat (Dadelkom), (–AD), 28 Sep 1988, B ӧsenberg & Rutherford 412 (NBG); Hermanus, 3 km SE of Gansbaai, Suikerbosrand, (–CB), 11 May 2005, Helme 3475 (NBG);Groot Hagelkraal, (–DA), 8 Mar 2012, Muasya 6477 (BOL); Buffeljacht farm, south of Buffeljagsberg, (–DA), 12 Mar 1979, Thompson 3962 (NBG, PRE); Rattle River Mouth, ± 8 km E of ‘Die Dam’, E side of mouth, c. 800 m from coast; (–DC), 7 Jun 1984, O'Callaghan, Fellingham & van Wyk 459 (NBG). 3420 (Bredasdorp): De Hoop Nature Reserve, (–AD), 11 Apr 1957, Levyns 10,706 (BOL [2 sheets]); De Hoop, Potberg Nature Reserve, Potberg farm, 2 km from coast along track to coast, (–BC), 9 Jul 1978, Burgers 1076 (K, NBG, PRE); Bredasdorp, Struisbaai, 2 km NW of Molshoop, (–CA), 28 Apr 2003, Helme 2668 (NBG); Agulhas, (–CC), 10 Apr 1948, Levyns 8821 (BM, BOL). 3421 (Riversdale): Brandfontein, (–AB), 13 Oct 1951, Esterhuysen 18,993 (BOL); 2 km from Duivenhoks river mouth, W side, (–BD), 28 May 1984, O'Callaghan, van Wyk & Fellingham 394 (NBG). 3422 (Mossel Bay): Goukamma Nature Reserve, (–BB), without date, without collector 163 (K). 3423 (Knysna): Robberg, Plettenberg Bay, (–AB), 25 Oct 1955, Esterhuysen 25,009 (BOL, K); Plettenbergbaai, Robberg, (–AB), Apr 1975, Viljoen 105 (PRE).

Figures

Fig. 1. Examples of plants from each of the seven known species of S.compar - S.pictus group found in southern Africa, showing the corresponding inflorescences and spikelets beneath each plant:A,H and O—S.compar; B,I and P—S.arenicolus, C,J and Q—S.pictus; D,K,and R—S.pseudoloreus; E,L and S—S.aureus; F,M and T—S.megacarpus; and G,N and U—S.filiculmis. The black scale bar beside the inflorescences and spikelets in H—N represents 10 mm, whereas the scale bar beneath O—U represents 1 mm.

Fig. 2. Examples of nutlets from six species of the S. compar - S. pictus group found in southern Africa: A—S. compar; B—S. arenicolus; C—S. pictus; D—S. pseudoloreus; E—S.aureus (immature); and F—S. megacarpus. The black scale bar represents 1 mm.The mature fruit of S.filiculmis is unknown.

Fig. 4. Documented locations of Schoenus arenicolus.